Flow visualization and acoustic consequences of the air moving through a static model of the human larynx
Flow visualization and acoustic consequences of the air moving through a static model of the human larynx
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DOI：
10.1115/1.2187042
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发表时间：
2006-06-01
影响因子：
1.7
通讯作者：
Ng, Terry T. M.
中科院分区：
文献类型：
--
作者：
Kucinschi, Bogdan R.;Scherer, Ronald C.;Ng, Terry T. M.
使用激光片照射的烟雾颗粒进行流动可视化，通过动态相似的 7.5 X 对称静态人体喉部模型（发散角 10 度，最小直径 0.04 厘米现实生活）获得气流结构的定性描述。使用电容式麦克风测量声带下游的声级。假声带（FVF）也包括在内。一般来说，声门流是层流和双稳态的。声门射流曲率随着流速的增加而增加，随着 FVF 的存在而减少。最低流速的声门出口流显示出弯曲射流，其对于所有几何形状都保持层流。对于较高的流速，离开声门的射流模式显示出层流射流核心，过渡到涡流结构，并在空间上导致湍流耗散。随着流入量的增加，该结构被缩短和收紧。狭窄的 FVF 间隙延长了流动结构，并通过加速流动而减小了射流曲率。这些结果表明，喉部流动阻力和离开声门的复杂射流结构很大程度上受到流速和假声带存在的影响。由于有序流动结构，声学后果根据四极型和偶极型声源进行了讨论。
Flow visualization with smoke particles illuminated by a laser sheet was used to obtain a qualitative description of the air flow structures through a dynamically similar 7.5 X symmetric static scale model of the human larynx (divergence angle of 10 deg, minimal diameter of 0.04 cm real life). The acoustic level downstream of the vocal folds was measured by using a condenser microphone. False vocal folds (FVFs) were included. In general, the glottal flow was laminar and bistable. The glottal jet curvature increased with flow rate and decreased with the presence of the FVFs. The glottal exit flow for the lowest flow rate showed a curved jet which remained laminar for all geometries. For the higher flow rates, the jet flow patterns exiting the glottis showed a laminar jet core, transitioning to vortical structures, and leading spatially to turbulent dissipation. This structure was shortened and tightened with an increase inflow rate. The narrow FVF gap lengthened the flow structure and reduced jet curvature via acceleration of the flow. These results suggest that laryngeal flow resistance and the complex jet flow structure exiting the glottis are highly affected by flow rate and the presence of the false vocal folds. Acoustic consequences are discussed in terms of the quadrupole- and dipole-type sound sources due to ordered flow structures.